we asked mitt romney about those outdid comments that have shaken up his campaign. is it just that when someone is inning for president in this day and age you can't always say what you believe? dr. jon lapook on a discovery that experts say could lead to a cure for breast cancer. and mark phillips with a killer for the irish republican army. she's told us her story, but will the police get to hear it. captioning sponsored by cbs pt this is the "cbs evening news" with scott pelley. >> pelley: good evening. president obama said today the united states is gathering evidence in the murders of the u.s. ambassador to libya and three other americans, but he said "there is no doubt that the assault on the u.s. consulate in benghazi this past september 11 wasn't just a mob action." evidence is growing that the murder of ambassador chris ssevens was planned and targeted. in new york today the president of libya met with secretary of ofate clinton at the united nations. he said that the libyan people had lost a friend. a year ago in libya a bunch of ragtag militias overthrew